Debugging vMix/RTMP Streaming Issues

This guide helps you troubleshoot common vMix and RTMP streaming issues, particularly when your stream status indicator blinks between red and yellow or stays yellow.

Understanding Stream Status Indicators

When streaming to Videosync with vMix or other RTMP encoders, the stream button shows different colors:

• Green: Stream is healthy and all frames are being sent successfully
• Yellow/Orange/Amber: Frames are being buffered and not every frame is sent to Videosync “in time”
• Red: Stream is disconnected or experiencing severe issues

Common Root Causes

If your stream blinks between red and yellow, or stays yellow, the issue is almost always on the encoder side or your connection - especially if it happens with multiple Videosync servers (eu-n-1, eu-n-2, eu-w-1).

1. CPU Overload (Most Common)

CPU usage over 70% is a clear sign that your computer is overloaded.

vMix documentation states:

“CPU % over around 70% is a sign that the computer is overloaded, try closing any other open programs or reducing the workload in vMix by using low quality recording and/or streaming settings.

Most recent Nvidia GPUs will allow you to perform 2 or 3 hardware encodes on the graphics card. If you aren’t using these, you could tick the Use Hardware Encoder box in the streaming settings. This will alleviate strain on your CPU.”

Solution:

• Enable hardware encoding in vMix stream settings (highly recommended)
• Close unnecessary programs
• Reduce streaming quality/bitrate
• Use lower quality recording settings

2. Slow Internet Connection

Upload speed too low for the selected streaming quality bitrate.

From vMix documentation:

“For example, if your internet connection provides 1Mbps upload speeds but the Streaming Quality preset is set to 1.5Mbps then the stream will be intermittent.

As a general rule, the Streaming Quality bitrate should be a value less than 80% of the Upload speeds available for the best results. (For example 1.6Mbps on a 2Mbps connection)”

Solution:

• Test your upload speed at speedtest.net
• Ensure streaming bitrate is less than 80% of your upload speed
• Consider using a wired connection instead of WiFi
• Try a 5G router if available

3. Streaming Provider Distance/Latency

Connection to Videosync server may be unstable or experiencing high latency.

Solution:

• Test different Videosync servers: eu-n-1, eu-n-2, and eu-w-1
• Run connection stability tests (see below)

Step-by-Step Debugging Checklist

Follow these steps when experiencing streaming issues:

Step 1: Check CPU Usage

1. Open Task Manager in Windows (Ctrl + Shift + Esc)
2. Look at the CPU percentage while streaming
3. If CPU usage is over 70%, your computer is overloaded

Fix: Enable hardware encoding:

• In vMix, go to Stream settings
• Tick the “Use Hardware Encoder” box
• This uses your GPU instead of CPU for encoding

Step 2: Test Internet Speed

1. Visit speedtest.net
2. Run a speed test and note the Upload speed (not download)
3. Compare with your streaming bitrate in vMix

Rule of thumb: Streaming bitrate should be less than 80% of upload speed.

Example:

• Upload speed: 5 Mbps
• Maximum recommended bitrate: 4 Mbps (80% of 5 Mbps)

Step 3: Check vMix Logs

vMix provides detailed logging that can help identify issues:

1. In vMix, check the streaming statistics while streaming
2. Look for dropped frames or buffer warnings
3. Review error messages in the vMix log

See vMix’s guide on diagnosing streaming errors for detailed log analysis.

Step 4: Test Different Videosync Servers

If blinking occurs on multiple servers, it’s almost certainly your encoder or connection:

1. Try streaming to eu-n-1.videosync.fi
2. Try streaming to eu-n-2.videosync.fi
3. Try streaming to eu-w-1.videosync.fi

Step 5: Test Connection Stability

Run ping tests to check connection stability:

Test connection to Videosync:

ping -t eu-n-1.videosync.fi

Test general internet stability:

ping -t 8.8.8.8

Watch for:

• High ping times (over 100ms)
• Packet loss
• Fluctuating ping times

Fix: If ping is unstable:

• Switch from WiFi to wired ethernet connection
• Test with a different internet connection (e.g., 5G router)
• Contact your ISP if issues persist

Step 6: Reduce Streaming Quality

If other steps don’t resolve the issue:

1. Lower the streaming bitrate in vMix
2. Reduce video resolution (e.g., from 1080p to 720p)
3. Lower the frame rate (e.g., from 60fps to 30fps)

Quick Solutions Summary

Problem	Solution
CPU over 70%	Enable hardware encoding in vMix stream settings
Slow upload speed	Reduce streaming bitrate or upgrade internet
Unstable WiFi	Switch to wired ethernet connection
Stream blinks on all servers	Check encoder performance and internet connection
Connection drops	Test with different network (cable, WiFi, 5G)

Additional Resources

• vMix: Diagnosing Streaming Errors
• vMix: Why does the Stream button sometimes show orange or amber?
• Speedtest by Ookla - Test your internet speed